The invention relates to a method for designing a drilling pattern for rock cavity excavation. For a round to be drilled in a face of the rock cavity the drilling pattern determines at least the locations and directional angles of drill holes in the coordinate system of the drilling pattern. In the method the designer draws up the drilling pattern with the assistance of design software. The object of the invention is described in greater detail in the preamble of the first independent claim.
The invention also relates to a software product in accordance with the second independent claim, the execution of which product on a design computer or the like produces operations required for the drilling pattern design.
Tunnels, underground storage hall and other rock facilities are excavated in rounds. In the face of a rock cavity there are drilled holes that are charged and blasted after drilling. One blasting detaches rock material from the rock for one round. For excavation of a rock cavity, a plan is made in advance, a theoretical excavation profile is drawn up and data on rock type, for instance, is determined. In general, the ordering party also sets various quality requirements for the space to be excavated. For each round, there is also designed, at the design board, a drilling pattern that is supplied to a rock drilling rig for drilling holes in the rock such that a desired round will be formed. When the drilling pattern is formed, it may be implemented in the rock drilling rig. When rock facilities of complex shape are excavated, it is not possible to use the same drilling pattern for drilling successive rounds, but each round may need a specific drilling pattern, or alternatively, the drilling pattern may need modification for each round.
Publication FI 105 942 B discloses a solution, in which the length of an existing drilling pattern may be continuously altered to correspond to the length of a round to be drilled at any particular time. The position of the starting face in drilling is shifted in the drilling direction or in the opposite direction. The locations of the drill hole end points are maintained, but instead, new starting points for the drill holes are determined on a new starting face or the directional angle of the drill holes is changed. In the solution of the publication the shape of the drilling round is maintained the same and just the length of the drilling pattern is adjusted.
Rock cavities may, however, include curved surfaces or the face of the round to be drilled may be inclined horizontally or vertically. Further, rock cavities may be sharply curved when observed in the working direction, whereby sheer directioning of the drilling pattern will not provide a desired sharp curve. In that case a sheer changing in the length of the drilling pattern as disclosed in said publication will not suffice. So, currently, complex face shapes of rounds have to be designed manually by drawing up a plurality of 2-dimentional projections so as to determine lengths, locations and directions of drill holes for the drilling pattern. This is slow and difficult, however. Moreover, as the design takes place using several different projections, it will be difficult for the designer to perceive the whole and to detect errors in the drilling pattern, if any.